Pump with variable suction/discharge amount and drive device composed of the pump and driving method thereof

A pump with variable suction/discharge amount, which is characterized in that the pump with variable suction/discharge amount includes a vane chamber body and a vane rotor, the vane chamber body having a vane chamber, the vane chamber being defined between a fixed wall member, a movable wall member and a movable vane chamber sleeve in the vane chamber body and having a capacity space, the vane chamber being partitioned by an impeller of the vane rotor in the vane chamber to form at least one eccentric vane chamber sections, at least one vane being disposed on the impeller, the number of the eccentric vane chamber sections being more than or equal to the number of the vanes, one side of the vanes in the eccentric vane chamber sections being a suction side, while one side of the vanes in the eccentric vane chamber sections being a discharge side, the suction side and the discharge side respectively having suction/discharge passages in communication with outer side of the pump, the fixed wall member being positioned in a fixed position in the vane chamber body, the movable wall member and the movable vane chamber sleeve being displaceable in an axial direction of the vane rotor relative to the fixed wall member to increase/decrease and change the capacity space of the vane chamber, so as to form a pump with variable suction/discharge amount.